1. Field of the Invention
The present invention relates to the technology of a microscope objective and a fluorescent observation apparatus.
2. Description of the Related Art
Conventionally, fluorescent observation apparatuses are used in observing the behavior of molecules inside biological specimen with utilizing fluorescent tags. By connecting fluorescence with specific biological molecules, fluorescent tags can be used in observing the behavior, the coupling status, the moving status, etc. of molecules in a biological specimen. A fluorescent tag can be a fluorescent dye, a fluorescent protein, a quantum dot, etc.
One of the recent trends is observation with multicolored fluorescent tags. With the multicolored fluorescent tags, plural types of molecules can be discriminated in an observation, and complicated events such as an interaction of molecules in a living specimen.
Using the multicolored fluorescent tags, a wider range of wavelength is required in the fluorescent observation than in conventional observations.
In addition, wavelengths of 440 nm and 405 nm are used for photoactiovation fluorescent protein such as Kaede, PA-GFP, etc. Such short wavelength light has not been frequently used in the conventional applications. As a result, there is an increasing request for an objective aberration-corrected in a wider wavelength range than the conventional objective.
The target of the observation in a living specimen was the structure of the cells, but the target recently is tending toward the behavior of molecules. As a result, the resolution in the focal plane and the optical axis of microscopes is getting higher request. In addition, since confocal microscopes are popular, an observation can be performed with higher resolution. That is, there has also been request for an objective of high numerical aperture to attain higher resolution.
The Japanese Published Patent Application No. H7-35983 and the Japanese Published Patent Application No. 2003-21786 disclose microscope objectives with high numerical aperture appropriate for fluorescent observations.